/*! ========================================================================
** Extended Template and Library
** Mutex Abstraction Class Implementation
**
** Copyright (c) 2002 Robert B. Quattlebaum Jr.
**
** This package is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License as
** published by the Free Software Foundation; either version 2 of
** the License, or (at your option) any later version.
**
** This package is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
**
** === N O T E S ===========================================================
**
** This is an internal header file, included by other ETL headers.
** You should not attempt to use it directly.
**
** ========================================================================= */

#ifndef __ETL__MUTEX_PTHREADS_H_
#define __ETL__MUTEX_PTHREADS_H_

#define __USE_GNU

#include <pthread.h>

#ifdef HAVE_SCHED_H
# include <sched.h>
#endif

_ETL_BEGIN_NAMESPACE

class mutex
{
    pthread_mutex_t mtx;
    pthread_t locker;
    int depth;
public:

    mutex()
    {
        pthread_mutexattr_t attr;
        pthread_mutexattr_init(&attr);
        // #ifdef PTHREAD_PRIO_INHERIT
        // pthread_mutexattr_setprioceiling(&attr,PTHREAD_PRIO_INHERIT);
#ifdef PTHREAD_MUTEX_RECURSIVE
        pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
#endif
        pthread_mutex_init(&mtx, &attr);
        pthread_mutexattr_destroy(&attr);
        locker = 0;
        depth = 0;
    }

    ~mutex()
    {
        pthread_mutex_destroy(&mtx);
    }

    // Exception-safe mutex lock class
    class lock
    {
        mutex *_mtx;
    public:
        lock(mutex &x): _mtx(&x)
        {
            _mtx->lock_mutex();
        }
        ~lock()
        {
            _mtx->unlock_mutex();
        }
        mutex &get()
        {
            return *_mtx;
        }
    };

    void lock_mutex(void)
    {
        if (!locker || locker != pthread_self()) {
            pthread_mutex_lock(&mtx);
            locker = pthread_self();
            depth = 0;
            return;
        }

        depth++;
    }

    bool try_lock_mutex(void)
    {
        return !(bool) pthread_mutex_trylock(&mtx);
    }

    void unlock_mutex(void)
    {
        if (depth) {
            depth--;
            return;
        }

        pthread_mutex_unlock(&mtx);
        locker = 0;
    }
};

_ETL_END_NAMESPACE

#endif